JPS608065A - Manufacture of polyurethane foam cushion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of making a decorative seat cover assembly for use on a motor vehicle seat. More particularly, the present invention relates to a method of manufacturing a dielectrically embossed seat cover assembly.

Traditionally, automobile seats have been constructed from supported and covered open cell polyurethane foam cushions. That is, the molded cushion is supported by a suitable frame, which frame members may include wires or other support portions disposed under or embedded within the foam. For the purpose of improving sitting comfort (3), cushions are also provided that use two or more different foams and have different stiffness and firmness depending on the seat area.

The seating surface and both sides of the cushion are covered with a decorative, usually colored material. This covering material is, for example, thin vinyl leather or a woven or knitted textile fabric. The cover material is usually attached to the form body and/or to the frame by suitable connection means such as hook rings, hooks, loops or other mechanical fasteners. As will be seen below, the use of a multilayer cover facilitates the creation of decorative or functional bulges or contours in the seating surface or seat back surface. Such multilayer covers (also referred to herein as seat cover assemblies) have conventionally generally consisted of at least three layers.
Consists of two layers. Typically, a relatively thin fabric layer (e.g., a tough, open-weave cotton or linen backing fabric material is used) that serves as the base layer, and a thin [approximately 12. The construction includes an intermediate layer of flexible polyurethane foam (up to 7 mm (3 A inches)) and a decorative covering outer layer of, for example, vinyl sheeting or a suitable fabric. These 3
The two layers are typically bonded together and integrated by an adhesive material.

It is often desirable to form decorative or functional contours or ridges or embossments on the visible surfaces of these laminated cover assemblies. One method of doing this, which requires considerable labor, is to compress the assembly by applying force from the top down and sewing the top layer to the bottom base layer. In many cases, a more efficient method would be by die bonding or dielectric embossing.

In dielectric embossing, a two-plate template press is used with a suitable die to form the desired embossed pattern on the surface of the seat cover assembly. Beneath each edge of the mold the foam is substantially fully compressed and the cover top layer is brought into close proximity with the base layer.

The workpiece between the two platens is exposed to extremely high frequencies (
An electromagnetic field (typically radio frequency) is applied. The radio frequency sensitive material within the workpiece is rapidly heated. In this case, the aim is to heat and melt the polyurethane foam which is present between the upper layer and the base layer and which is compressed under the edges of the mold. Upon curing, the molten foam bonds the upper layer to the base layer, leaving the desired embossed pattern in the cover material.

Typical polyurethane foam slab materials are not easily dielectrically heated. This material is not a dielectrically N-loss material. However, dielectric
Compositional formulations of heatable polyurethane foams are known and such compositions have been manufactured, and materials such as and are already used in relatively thin dielectric embossed laminate sheet cover assemblies. . However, the high content of molten foam makes the embossed polyurethane seam extremely stiff and hard. Such hardness is undesirable for automobile seats. Furthermore, if the foam layer is very thick, the embossed structure will be distorted. Heretofore, decorative embossing of relatively thick urethane foam layers such as required or desired for seat cover assemblies has not been possible with urethane foam dielectric embossing techniques.

It is therefore an object of the present invention to provide a decorative, dielectrically embossed urethane foam sheet cover assembly which can form a desired embossed pattern regardless of the required overall thickness of the foam layers of the assembly. An object of the present invention is to provide a method for manufacturing a three-dimensional object.

According to a preferred embodiment of the invention, these and other objects and advantages are achieved by starting (7) with a two-layer polyurethane foam block. One of those two layers
One is a polyurethane foam layer of composition that can be dielectrically heated. The other layer is a layer of polyurethane foam slab material common for dielectric heating. The thickness of the 1L heatable layer is determined by the desired embossing pattern to be formed on the cushion. The total thickness of the two layers is determined by the foam thickness required for the seat cover assembly.

A cover layer is applied over the two-layer foam laminate over the dielectrically heatable layer. The cover fabric layer can consist of one or more layers of suitable decorative material. It can be a vinyl sheet, for example. Still, it can be a woven or knitted fabric of nylon, polyester knit or other suitable fibers. An intermediate mat layer may be interposed below the cover material. Furthermore, the composite polyurethane foam laminate may be provided with an adhesive layer that serves to bond the cover material.

(8) A suitable base layer, such as a backing cloth, may also be bonded to the bottom surface of the composite polyurethane foam laminate.

A desired embossed pattern or recessed pattern can be dielectrically formed on the sheet surface of the cover assembly created with the above configuration. That is, a seat cover assembly to be processed (hereinafter also simply referred to as a workpiece) is placed between two platens of one dielectric press, and a die blade formed to the contour of a desired pattern is placed on one of the workpieces. Bring it into contact with the top layer of the cover. This creates a depression in the pressed surface with a depth approximately corresponding to the thickness of the dielectrically heatable polyurethane foam layer. In this state, a high frequency electromagnetic field is applied. At this time, only the upper layer of polyurethane foam located below the indented cover layer is melted. The cover layer is then bonded to the lower, unheated layer of polyurethane foam. The different foam layers of the two presses that make up the polyurethane foam laminate work together to form a highly practical seat cover assembly with a pleasing appearance, so that the thickness of each layer is independent of each other. In this way, both an attractive embossed pattern and a functionally useful seat cover can be controlled. In this way, attractive functional or decorative contours can be created on the upper side of the seat cover, regardless of the overall thickness of the foam.

Note that it is not necessary to have one layer of the cover present during the embossing of the two-layer polyurethane foam laminate. A sheet of suitable cover material can then be adhesively bonded to the contoured surface of the dielectrically embossed foam laminate. However, the cover is more imitation/
If a stitch pattern or other elaborate pattern is desired, the cover layer must be placed on the foam laminate at the time of embossing.

The present invention will be explained in more detail below with reference to the drawings.

In FIG. 1, an assembled automobile seat 10 is shown. Seat 10 includes a seating or seat portion 12 and a backrest portion 14. The seat portion 12 and the back portion 14 both have a contoured or convex portion 1
It has a pattern of embossed recessed lines 16 resulting in 8.

Each section includes at least one foam material cushion 30
and a suitable metal or molded plastic reinforcement or frame member 32.

In FIG. 1 these parts are visible only in the section shown broken away. This is because the seat assembly is covered with a suitable cover material 28. The cover material 28 is part of a seat cover assembly described below. The present invention relates to a method of forming a decorative dielectric embossed pattern on such a seat cover (11) assembly.

FIG. 2 is a cross-sectional view taken along line 2--2 in FIG. 1 of a seat having a seat cover assembly made by the method of the present invention.

The illustrated seat cover assembly includes a two-layer polyurethane foam laminate having an upper layer 20 and a lower layer 22. The two foam layers are bonded at their interface 24 by a suitable adhesive. The upper polyurethane layer 20 is the layer on which the embossed pattern is formed, and the composition of this layer must be sensitive to dielectric heating. The composition of such polyurethane foams is known and such polyurethane foams are readily available on the market. The features of this layer 20 will be discussed in more detail below.

Lower polyurethane foam If! 122 is a common urethane foam slab material. This material is not sensitive to dielectric heating. That is, it does not heat up easily (12) even when exposed to high-frequency electromagnetic radiation. The two foam layers 20 and 22 are bonded together at an interface 24 by any suitable adhesive.

Underneath this foam layer 22 is a suitable base layer 26. This base layer 26 may be a tough, open-weave cotton or linen cloth or other fibrous or plastic sheet. Neither the particular composition of this layer 26 nor its presence itself is essential to the method of the invention.

A decorative cover layer 28 is placed over the two-layer foam laminate, more particularly over the upper foam layer 20.
exists. This cover layer 28 is a two-layer foam laminate 2
Seat cushion 30 extending further below than 0.22
and may extend to cover the frame member 32 as well.

Typically, this cover layer is secured to frame member 32 by suitable means.

Cover layer 28 may be constructed from vinyl sheet material. It may also be a woven or knitted fabric of fibers. What is needed is to have the durability and decorative properties desired in the intended seating application. In practice, this cover layer may consist of several layers. For example, a cloth sheet may have a thin mesh or mat layer (for breather purposes, etc.) under the sheet layer, and an adhesive layer below the mesh layer, and the adhesive layer will hold the cover layer together. It could be configured to bond to the urethane foam layer 20. The exact configuration and shape of this cover layer is also critical to the practice of the invention. The cover layer can be any layer that is compatible with the underlying polyurethane foam and the remaining sheet components. Also shown in the drawings is a decorative tabby section 34 cut into the edge of the sheet and sewn into the cover material 28. It is not essential to the present invention to include such a decorative seam. However, the cover 28 and the two-layer polyurethane foam laminate 20.22 described above are essential components of a seat cover assembly manufactured by the method of the present invention and used on a motor vehicle seat.

As mentioned above, urethane foam materials in the form of slabs that are dielectrically heatable are available on the market. Thermosetting polyurethane foams must be modified to contain thermoplastic components that can be heated by dielectric heating methods. For example, thermoplastic resins such as plasticized polyvinyl chloride, polymethacrylic acid, polystyrene, or polyethylene can be mechanically blended in powder form to modify polyurethane foams. Another method of obtaining dielectrically heatable polyurethane foams is to chemically graft thermoplastic block polymer segments onto the polyurethane chains. Examples of thermoplastic block polymers include polystyrene acrylonitrile block polymers. The polyurethane foam to be the -1-side layer of the double polyurethane foam laminate (15) used in the production of the cover assembly of the present invention, either by mechanical or chemical methods, has a dielectric Contains thermoplastic components that are lost.

Furthermore, what should be understood when implementing the present invention is:
The thickness of the Rule 21 polyurethane foam layer 20 is determined primarily by the depth of the recess line 16 to be formed in the seat cover assembly 20.22.28. Foam thicknesses up to 3 A inches can be embossed without excessive dimples, seam stiffness or distortion of the seat cover assembly. On the other hand, the thickness of the polyurethane foam layer 22, which cannot be dielectrically heated, can be determined to meet other requirements of the seat cover assembly, such as structural needs.

Dielectric embossing (16) of the laminate consisting of the dielectrically heatable polyurethane foam layer 20 and the non-dielectrically heatable polyurethane foam layer 22 is carried out as follows.

The laminate workpiece, with or without cover material 28 overlaid thereon, is placed between a pair of bratens in a dielectric embossing press.

Mounted on one of the platens are strip dies arranged to apply pressure to the upper surface of the workpiece to form the desired pattern of indentations. The diet descends and compresses the foam layer 20, causing the cover layer 28, if present, to be brought into close proximity to the foam layer 22, creating a press-fit indentation as indicated by reference numeral 16 in FIG. It is formed. At this time, the dielectric embossing press irradiates radio frequency energy so that the layer 20 is selectively heated, particularly in the compressed areas located below the die member. This causes the compressed foam in that area to melt and bond the cover layer 28 to the foam layer 22.

In this case, prior art methods required that the cover layer 28 be completely press-fitted through the entire thickness of the foam laminate to the point where the cover layer contacted the base layer 26. The method of the present invention avoids that need by using a dual (dielectrically heatable layer and non-dielectrically heatable layer) foam cushion pad.

If cover material 28 is present during dielectric embossing, it is bonded to the underlying foam layer 24 in the pressed-in areas, as shown in (1). If cover material 28 was not present at the time of embossing, it can be adhesively bonded to the upper foam layer 20 afterwards, thereby completing the seat cover assembly.

The present invention can be implemented in various ways. The decorative polyurethane cushion made by the method of the present invention can constitute one complete seat cushion by itself or only a portion of one complete seat cushion, i.e., a neatly trimmed seat cover. It is also possible to construct only the assembly part. It should further be appreciated that the underlying structural polyurethane foam layer itself can contain multiple dissimilar polyurethane foam materials having different stiffnesses or hardnesses. This allows the seat to have a desired hardness distribution suitable for the seat.

Although the invention has been described with respect to specific embodiments, it is to be understood that various other embodiments are possible within the scope of the invention. Accordingly, the scope of the invention should be determined by the following claims.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an automobile seat having an embossed seat cover assembly comprising a seat cushion and a back cushion and made by the method of the present invention. FIG. 2 is an enlarged cut-away cross-sectional view taken along the plane 2--2 of FIG. 2 illustrating how two polyurethane foam layers according to the method of the present invention may be utilized in a cushion pad. FIG. Explanation of symbols of main parts> 10... Automobile seat cover assembly 12.14... Polyurethane foam cushion 16... Embossed pattern 20・
......First layer 22...Second layer 28...
・・・・・・Layer of cover material (20)

Claims (1)

[Claims] 1. A method of manufacturing an embossed and covered polyurethane foam cushion by embossing an embossed pattern on the foam cushion by dielectric embossing; A foam layer with a dielectrically heatable composition,
forming a laminate containing two polyurethane foam layers, first and second, wherein the second layer is a foam layer of a composition that is not melted by such dielectric heating; (1) overly bonding a first layer of the laminate to the second foam layer, melting the first foam layer and bonding the pressed depressions in the desired embossed pattern to the second foam layer. ) embossing the embossed pattern into the first polyurethane layer while dielectrically heating the first layer, the initial thickness of the first layer forming the desired embossment. and wherein the total thickness of the first and second foam layers is sufficient to provide the desired cushioning. 2. In the method of manufacturing an embossed covered polyurethane foam cushion according to claim 1, the layer of cover material is applied to the first layer of polyurethane foam before the embossed pattern is embossed into the first layer of polyurethane foam. and bonding the laminate to the laminate so as to cover one foam layer. 3. A method of manufacturing an embossed covered automobile seat cover assembly comprising at least one embossed covered polyurethane foam cushion according to claim 1. ) applying a layer of cover material to the laminate over the first foam layer and extending beyond the first foam layer as far as necessary to trim the automotive seat cover assembly; A method characterized by joining.